Gyroscope precessor and follow-up



Dec. 14, 1948. E POlTRAs ET AL 2,456,020

GYROSCOPE PRECESSOR AND FOLLOW-UP Original Filed-Aug. 10, 1935 3 Sheets-Sheet l ATTORNEY Dec. 14, 1948. E. J. PolTRAs ET AL l 2,455,020

GYRoscoPE PREcEssQR AND FoLLow-UP Original Filed Aug. lO, 1935 I 3 Sheets-Sheet 2 6 iig? 5 i?? "L2 E 66 -1 '75 G mu/, i

77 75 RPI lo A d l 2g INVENTOR Edwa/rd/ J. Po ras .Ia/nuls D. Tea/r 76 729 Rl 685 ATroRNx-:Y

Dec. 14, 1948. E. J. PorrRAs ET AL 2,455,020

GYROSCOPE PRECESSOR AND FOLLOW-UP Original Filed Aug. 10, 1955 3 SheQtS-Sheet 5 LPA- 64 INVEN-rorgs J. POL tras a/meslLTeam ATTORNEY Patented Dec. 14, 1948 GYROSCGPE PRECESSOR AND FOLLOW-UP Edward J. ioitras, Pasadena, Calif., and James l). Tear, Great Neck, N. Y., assignors to Ford Instrument Company, Inc., Long Island City, N. Y., a corporation of New York Continuation of application Serial No. 35,682, Au-

gust 10, 1935. This application April 11, 1939,

Serial No. 267,248

This application is a continuation of our application Serial Number 35,682, filed August 10, 1935, now abandoned.

The invention herein disclosed. relates to a system and mechanism for controlling and reproducing the movements of a gyroscope, and in particular to mechanism for applying precessional forces to a gyroscope and controlling a motor to drive an object in accordance with the relative movements of a gyroscope with respect to its mounting.

In certain applications of the gyroscope, it is necessary to apply controlled precessional forces to the gyroscope and to drive an object in accordance with the movements of the gyroscope. Such mechanism must be such that there is no reaction on the gyroscope other than that intentionally effected because the gyroscope reacts to any forces applied thereto. Heretofore, various mechanisms have been utilized for accomplishing these functions, the most common being the application of precessing forces mechanically and following mechanism intermittently operated by relative movement of electrical contacts, contact between which is made and broken by relative movement of the gyroscope and the power driven gimbals.

An object of this invention is to provide a mechanism for this purpose which is more compact, smoother in operation and more satisfactory from the standpoint of performance than has, heretofore, been available. To this end, the mechanism provided includes a motor for driving a driven object in accordance with the movements of the gyroscope about an axis thereof and controls therefor which are actuated by movement of the gyroscope. In the system there is employed two such motors, one for reproducing in a driven member the movement of the gyroscope about one axis and the other for reproducing in a driven member the movements of the gyroscope about another axis at right angles to the rst mentioned axis. The controls for the motors include means for exerting forces on the gyroscope to eiect precession of the gyroscope.

A feature of the inventon is the fact that precession of the gyroscope is eiected hydraulically.

A system embodying the invention is disclosed in the accompanying drawings in. which:

Fig. 1 is a diagrammatic representation. of the system;

Fig. 2 is a fragmentary plan of the gyroscope mounting illustrating the control block;

Fig. 3 is a fragmentary elevation of the gyroscope and control block, partlyin section;

Fig. 4 is a plan of a valve block; f Fig. 5 represents a sectional elevation of the same; and

Fig. 6 is a longitudinal section of a force generator.

General description In the system as illustrated in Figure 1, the

gyroscope I is mounted in a gimbal system that is supported by a frame 2 pivotally mounted in standards 3 and il for oscillation about an axis. A A. Within the ring frame 2, there is mounted a phantom ring 5 for oscillation about an axis B-B at right angles to the axis A-A of the frame. A gimbal ring 6 is pivotally mounted within the phantom ring 5 about an axis C-C parallel to the axis B--B about which the phantom ring is pivotally mounted. The gyroscope proper is pivotally mounted within the gimbal ring 5 about an axis D-D perpendicular to the axis C-C about which the gimbal ring 6 is mounted. This arrangement allows free movement of the gyroscope.

, The frame 2 follows the movements of the gyroscope about the axis D-D and carries the phantom ring with it in its movement about this axis. The phantom ring is driven directly to follow the movements of the gyroscope about the axis C-C, and, thus, the phantom ring follows the movements of the gyroscope about both the axis D-D and C-C. This is accomplished by hydraulic motors 'I and 8 which drive the phantom ring and the frame respectively, the operation of which motors is controlled by control elements 9 and I0 respectively, extending from a control block I I mounted on the phantom ring 5. The control element 9 is secured to the gimbal ring 6 by a pin I2 and the control element I0 is secured to the gyroscope by a similar pin I3 so that movement of the gyroscope about the axis C-C relative to the phantom ring 5 effects movement of the control element 9 and movement of the gyroscope about the axis D-D relative to the phantom ring and frame effects movement of the control element I0.

The motor I is connected to a shaft I4 on the end of which there is secured a bevel gear I5. The bevel gear I5 meshes with a bevel gear I6 mounted upon a shaft I'I. The shaft I1 extends through the bevel gear IE, one end I'Ia extending to any mechanism or apparatus that it is desired to drive in accordance with the movement of thel gyroscope about the axis C-C. The other end I b of the shaft extends through and is journaled in the standard 4 in which the frame 2 is journaled. The end I 'lb of the shaft extends through' the center of the trunnion 2a extending from the frame 2 and journaled in the standard il. Upon the end of the shaft, there is secured to the shaft a bevel gear IB which meshes with a bevel gear I9 secured on a jack-shaft journaled in bearw ing brackets 2l and 22 extending laterally from the frame 2. Secured to the gear Ill, there a pinion 23 which meshes with an arcuate rack 24 secured to a bracket E extending from the phantom ring 5. Through this train of gears and shafts, the motor l operates the phantom ring about the axis B-B.

The motor 8 drives a shaft 2t through a shaft 2T and bevel gears 28 and 2li mounted upon the shafts 26 and 2 respectively, The shaft 25 also extends through the bevel gear 52E which is sen cured thereon and one end 2Go; extends to a mechanism that it is desired to drive in accordance with the movements of the gyroscope about" the axis A--A. The other end 2th of the shaft 26 extends through and is journaled in the standard Iy at aporlt. below the shaft il. On the end of the shaft 2Gb there is secured a spur gear 3o which mesheswith a segmental gear 3i secured to the frame 2. Through this mechanism, the motor 8 oscillates the frame about the A-A.

The hydraulic medium used for operating the system is preferably oil, and oil under pressure is supplied by pumps 32 an one for each of the two motors and the two control elements. The high pressure sides of the pumps 32 and 33 are connected by leads 3ft and respectively to a valve block SI5 mounted on the standard S, Relief valves 34d and 35a are connected to leads 34' and' 35 respectively and lto the exhaust line4 3l.

The ports and passages ci the controls 9 and Ill and the control block 5I communicate with the valve block through portsand passages leading through the trunnion. 2l; which extends between the frame 2 and the phantom ring 5, the arms Ec and 2d' of the frame, trunnion by which the frame is pivotalfy mounted in the standard 3, and the standard rlhe exhaust lead 3l' extends between the valve block. the oil supply tank ,38' to which the pumps 32 and are connected by leads 39' and til respectively. The motor 'I is also connected to the valve hloclr through leads 4I and 42'. Similarly, the motor il is connected to the valve block through leads and dil.

The control elements il and lli in addition to acting as control elements for controlling the operation of the motors l and 8, also act as processing elements through which forces are applied to the gyroscope to effect the precession of the gyroscope. When acting as a part of the system for precessing the gyroscope, the forces exerted on the gyroscope by these elements are controlled by force generators @il and da'. The force generator 55 is connected to the valve block by two leads fil and Il@ and to the exhaust lead 31 by a lead 49. Similarly the force generator 4B is connected to the valve block by leads 5U and 5I and to the exhaust lead ill by a lead 52.

The motor controls The manner in which the various controls, force' generators and valve blocks are constructed and operate is illustrated in Figures 3 to 6 inelusive. The individual controls for the motors are separate and distinct, but they are identical for the two motors. Therefore, only the control for the motor 8 will be described in detail, it be ing understood that the control for the motor l is identical in. all respects. The ow of uid to the motor 8, and, therefore, the operation of pressure of the oil supplied to the motor in accordance with the drop in pressure across the motor plus a constant pressure. In this way there is maintained constant drop in pressure across theinain valve and a more delicate control of the motor is assured.

Throughout the following description and in the drawings, the following characters and legends have been used and indicate on the drawings the interconnection oi the various ports:

HP-=High or pump pressure.

MP=Motor pressure.

LP=Low pressure obtained from a reducing valve 56. (Fig. 5').

EzExhaust.

R=Reference volume.

PRPr'Precessing reference pressure.

PP-:Precessing pressure.

The various ports in the Valve blocks are desigu hated by the various combinations of letters above indicated and a numeral. Those ports vhaving as a part of the designating characters one of the above combinations of letters are interconnected and are connected to the oil supply or exhaust indicated by the combination of letters.

The valve 53 is operated hydraulically, in a manner which will hereinafter be described in detail. through a piston 53a formed on the end thereof. The valve 5S has two reduced sections 53h and 53o spaced longitudinally thereof. rlhe lower end of the valve chamber is connected through a port EI to the exhaust lead 3l so that the valve is lfree to move longitudinally in the valve chamber. The valve controls communi cation between the ports E2 and MPS, between ports MP'I and E3, and between port EPI and ports MPI and MP' I. The ports MPI and MP'i communicate respectively with the motor leads 43' and M; the ports E2 and communicate with the exhaust lead Sl and the port HPI communicates with the pressure lead 34. In the position illustrated in Figure 5, the valve laps the ports E2, HPI and E3 so that when the valve is in this position the motor 8 is not operating. If the valve is moved upwardly, for example, from the position shown in Figure 5, the ports MPI and E2 will be placed in communication and also the ports HPI and MPI will be placed in communication. Oil will thus flow to the motor through the port MP I. if on the other hand the valve 53 is moved downwardly from the position illustrated in Figure 5, the port MPI will then communicate with the port HPI and the port MP'I will communicate with the exhaust port E3 andthe oil under pressure will flow to the motor in the opposite direction.

The `regulating valve 5d is also a piston valve and has a reduced section 54a which is adapted to control communication between the ports HPS?. and E4. This regulating valve, as heretofore stated, is operated so that the pressure of the oil supplied by the pump is equal to the pressure drop across the motor plus a constant pressure so that the drop in pressure across the valve 53 is maintained -constant. The relation may be indicated by the following formula: y

HP=LP+ (MPH-MPL) in which HP is the working or pump pressure as regulated by the regulating valve, LP is a constant low pressure supply which is obtained by a reducing valve 5E located in the block 3B, MPH is the pressure of the oil in one of the motor leads, the high pressure side of the motor, and MPL is the pressure on the other motor lead, the low pressure motor lead.

` The valve 54 is actuated to provide this regulation through the mechanism illustrated in Figure 5. The valve 54 is mounted in a bore or an elongated vchamber 55 of circular cross-section extending through the block 36. Below the valve, and spaced therefrom there is a block 51 secured in'a definite position in the chamber 55 by a set screw 58. The block 51 is bored axially and there is a rod 59 extending through the block and slidably, mounted therein. Below the block 51 and spaced therefrom there is another block 60 which is slidably mounted in the chamber 55. The block 6B; lkevthe block 51, is bored axially thereof and through this bore a rod El extends and is slidably mounted therein. The rod Sl is provided with an enlarged head Sla to form an abutting surface for the end of the rod 59. A third block 62 is slidably mounted in the chamber 55 and is adapted to abut against the lower end of the pin 6I. Between the blocks E0 and 62 there is provided an abutment pin 63 which extends into the chamber between the blocks and prevents the block 50 from moving too far in the direction of the block B2. The slidably mounted blocks 60 and'62 act in the nature of pistons in a manner hereinafter described.

A low pressure port LPI communicates with the chamber 55 between the valve 54 and the upper end ofthe block 51. a port MP2 communicates with the chamber 5.5 between the lower end of the block 51 and the upper end of the block 60, aport MP2 communicates with the chamber 55 between the lower end of the block 5U and the' upper end of the block 62. and a port MP3 com-v municates with the chamber 55 below the lower end of the block 62. The block 62 has its lower end reduced as indicated so that the port MP3 will not at any time be cut off from communication with the lower end of the chamber 55. The ends of the chamber 55 are closed by the cap 64 and the bottom plate 65, which also close the ends of the chamber for the valve 53. The ports HPI and HP2 are connected through a common lead to the high pressure lead 34 of the pump 32; the port E4 is connected to the exhaust; and the port LP! is connected to the low pressure supply. The ports MP5, MP2 and MP3 are connected together and to the motor lead 43 and the ports MP'I and MP2 are connected together and to the motor lead 44. In the valve 54 there is a passage 54hwhich connects the annular chamber formed by the reduced portion 54a of the valve with the valve chamber above the valve 54. Since this reduced portion of the valve is, as will be apparent from the drawing, always connected to the pressure port HP2, the pressure of the oil in this port will act against the end of the valve tending to force the valve downwardly from the position illustrated in Figure 5 and thus open the pressure port HP2 to the exhaust port E4 and lower the pressure in the pressure line to which the port HP2 is connected.

, 'Ijhelzvforce exerted by the oil in the chamber;

6 above the'valve 54 is resisted bythe pressure of the oil admitted through-the low pressure port LP! and the diiierence between the pressure'in the ports MP2 and MP2.y It will be observed that pressure of the oil in the port MP2 acts upon the block El) tending to move the block downwardly against the pin 63. Pressure in the port MP2 acts between the blocks 60 and62 tending to separate these blocks and move the block 60 upwardly and the pressure of the oil admitted through the port MP3 tends to move the block 62 upwardly against pin 6|. For the purpose of explaining the action of this mechanism, let us assume for the moment that MP is the pressure of the Voil on the high pressure motor lead, and MPlis the pressure of the oil on the low pressure side of the motonthat is, that the valve 53 is moved downwardly from the position shown. In such an event, the pressure o'f the oil admitted through the port MP2 will cause the block 60 to abut lagainst theabutment 63. The pressure of4 the oil admitted throughthe port MP2 will act,

upon the end ci the block $2 and the pressure admitted through the port MP3 will act upon the opposite end of the block 62. Thus,` the force exerted upon the pin 6i will be proportional to the difference between the pressure `of the oil admitted'through the port MP2 and the port MP3. This force will act through the rod 59 on the Valve 54 and addedfto that force there will be the -force of the oil admitted through the low pressure port LPl. The valve 54 will thus .be-

actuated in accordance with the formula. as given above.

If the main valve kt'alifis so operatedthat the'port MP i becomes the high' pressure port of the motor and the port'MPifb-:Comes the low pressure port of the motor, so that the port MP2 admits oil at the high pressure and the ports MP2 and MP3 acimit oil at the pressure of the exhaust side of the motor, the valve 54'will be regulated again in accordance withfthe `formula given above, that is;

in accordance with the sum of the low pressure plusthe difference between the'pressure in the port MP2 and the pressure in the port MP2. The operation will be 'as follows: The pressure of the oil admitted through .the port MP2 being greater than the pressure of oil admitted throughv the port MP3, the block 62 will be forced against the bottom plate 55 and the pressure of the oil will act to move the bloclr` 55 upwardly carrying the rod 6| and pressing against= the end of the pin 59. Movernentrof'the block upwardly will be resisted by the low pressure oil in the port MP2 so that the' force on the pin 59 will be proportional to the difference between these two oil pressures and the force on the valve 54 will be the'sum of this force and the force `exerted by the low pressure oil ad?v mitted tthrough th-e low pressure port LPI. In'

this manner the drop-in `pressure across the valve 53 between the high pressure lead of `the mot-or.

the valve opening. and, therefore, the speed-of'4 the motor is proportional tothe valve opening.

. vAs heretofore stated', :the valve 53 is operated. hydraulic-ally through. the piston 53a. The piston 53a is a diierential piston4 The surface area. of the upper sideof :this piston asseen in Figure 5 is approximatehr twice as great'as that of the low-"" ersurface of thepistonf. Be-tween the l0`Wer"sur-I:`

face of. the. pistonand .the end of the; chamber in which the piston. -opera-tes' there is a low pressureport LP2 `communicating with the chamber so that oilat a. constant pressure acts upon the lower surface of the piston'. That part of the chamber above'. the piston forms a part of a reference volume, and as will be evident, the valve may be operated by increasing or decreasing thepressure of the.- referenee volume abovev or below one-half of thev low pressure'sincethe area of the piston upon. which` the reference volume acts is twice as large asv the area upon which the lowy pressure acts.. It is. inthis way that the valve 53v is operated.

'Ihe pressurev of the reference volumeA is con.- trolled byv a pilot. valve 66y mounted in the valve block IIf and secured to the controlL element III, which constitutes a valve sternv (Fig. 3). The valve 86 is hollow for a portion. of its length and the rod I extends into the valve and is secured therein: through a pivot BTI?. This pilot valve is slidably'mounted in a plunger 68' having portsand passages which are controlled bythe valve. The valve. has-'twoireduced portionsft 6a and 66h spaced longitudinally thereof. The plunger E8 in 'which' the valve E6 is slidablvu mounted is operated upon by differential pressures and the area of the lower surface 88a is equal to twice the area of the surface BB'b. The plunger is slid-ably mounted in achamber I2czy formed in the valve block II. The chamber Iz2bs formed' below the plunger 68 consti- .tutes a.- part of' the.4 reference volume and communicates through a port RI and passages R3 in the frame 2, trunnion 2e, and standard 3 with a `port'RZ communicating'with the reference volume chamber 36ak above the piston 53a in the valve block 36,` (Fig. It will thus -be .seen that movementv of. .the plunger downwardly increases the pressure ofthe oil. in the reference volume chamber which actsv upon the larger surface of the piston 53a secured yto the valve 53. Likewise upward movement of' the plunger 68 reduces the pressure in this chamber. Under normal conditions with the plunger 68 and the valve 53 in the position illustratedin Figures 3 and 5; the pressure in the vreference volume is one-half lof the pres*- sure of the lowV pressure supply'.

Movement of the valve 66 admits low pressure toi and; exhausts low pressure from the chamber I'2c formed between the upper end of the plunger and theend. of the plunger chamber I2a, thus effecting either downward or upward movement of .the plunger toeffect'the operation of the valve 53. This is'aceomplished throughy a low pressure port LP3; extending through t'he plunger and connectedl by'passage LPdA through the frame 2', trunnion 2e and standard y3v with the low pressure port LPI invalve-block 3S;v and by an exhaust port E5 like wise extending radially through the plunger and communicating' with lead 31 through passage El through the same ports. The valve 66 controls communication between these ports and apassage 68e which communicates with; the chamber I2C. For example, if the valve 6'6 is'moved downwardly from the position illustrated, the port LP3 is placed into communication with the passage 68e and pressure is admitted to the chamber I2c thus causing theA plunger yto move downwardly. On the other hand', if. the: valve 66 is moved upwardlyl from the position shown in Figure 3, the exhaust port E5 is placed into-communication with the-passage 68e andthe pressure in the chamber I2cis reduced so that'the' plunger moves upwardly andv the pressure of the. reference volume is reduced. This. arrangement provides what might be termed a power amplifying systemA and` by means of it, the valve 53 is actuated vto control the motor by an innnitesimal pressure on the valve 66. There is, therefore, practically no reaction on the gyroscope to eiect the control of the motor.

In the follow-up action of the motor 8,y the operation of the system is as follows: Assume that the gyroscope is moved about the axis D-D by the application of a processing force through the control element so that the valve 66 is moved downwardly. In the manner heretofore explained, oil under the low pressure is admitted to the chamber I2C and the plunger 68 moves downwardly increasing the pressure inthe chamber |21) and consequently in the chamber 36a in the valve block 3&3. This causes the valve 53 to move downwardly from the position4 shown in Figure 5. Under such circumstances, as heretofore explained, the port HPI andthe port MPI are. connected together and the ports MPI and E3 are connected together. The regulating valve is of course functioning at all times and consequently the drop inpressure between the portk HPI and the port MPI is constant, as explained above. The motor 8 is thus operated, and through the shafts and gears actuates the frame 2 about thev axis A--A in a direction to follow the movement of the. gyroscope. As the frame moves, the phantom ringv also moves about the axis A-A and consequently the valve block il follows the movement of the valve. This is a relative movement and therefore alters the relation of the valve to the plunger. It will be understood of course that wheny the valve was moved the plunger moved in the same direction as the valve. In fact the diierence inf movement between these two elements is imperceptible. The plunger continues to move until the communication between the low pressure port LP3 and the chamber lic is cut oir. On movement of the frame, through the operation of the motor, there is the same effect as thoughr the valve 66 were moved in the opposite direction, thus. placing Athe chamber I2C in communicationwithI the exhaust port E5. The pressure in the chamber I 2c is thus reduced and the plunger movesA upwardly until this communication is cut oil at.`

which time the operation of the motor ceasesas the valve 53 is then in the position illustrated in Figure 5. The operation of the system is the. same in the reverse direction.

Synchronieing value It will be apparent that in the operation of the system as described above, there will be a. lag between the movement of the gyroscope and the movement of the frame. In order to remove this lag, and have the frame and the gyroscope operate synchronously, there is provided a synch'ronizing valve S9. The synchronizing valve 69 is a needle valve and cooperates with a valve seat I2d to control communication between a passage I2e formed in the valve block and communicating with the reference volume chamber I2b, and a passage I2`f formed in the valve block I I. A port I 2g extends laterally of the passage IZf. Communication between this port I 2g and the low pressure port LP3 and the exhaust port E5 is controlled by movement of the plunger. The plunger has two reduced portions 68e and 68j. These reduced portions are on opposite sidesr of the port I2g and are such' that when the plunger 68 moves downwardly, the port I2g is connected to the low pressure port LP3 and when the plunger moves upwardly, the port I2g is. placed into communication with the exhaust port E5.

Thus when the plunger moves downwardly from the position shown to increase the pressure in the reference volume I2b oil under low pressure flows from the port LPS through the port I2y, the passage I2f, valve IZd, passage I2e to the reference volume I2b and thus augments the effect of the movement of the plunger by gradually increasing the pressure in the reference volume I2b. Through the same ports and passages, when the plunger moves upwardly to decrease the pressure in the chamber I2b, the chamber I2b is placed in communication through the needle valve with the exhaust port E5 thus augmenting the effect of the plunger in reducing the pressure in the reference volume chamber |213. The needle valve is adjusted empirically and its effect is to advance the movement of the valve 53 so that the frame operated by the motor is advanced into synchronism with the gyroscope.

The above describes the manner in which movements of the gyroscope are reproduced by the frame and any object driven by the shaft 26. In the same manner, the motor I is controlled to cause the phantom ring to follow the movements of the gyroscope about the axis C-C and to drive any object coupled to the shaft I1 in accordance with the movement of the gyroscope about this axis.

Precessz'ng mechanism The manner in which precession forces are applied to the gyroscope in this system will now be described. For each control element the precessing mechanism is also duplicated so that there is individual control for precessing the gyroscope about the axes C-C and D-D. These controls are identical and therefore there will only be described the mechanism utilized in applying a force to the gyroscope through the control element I to eiect precession of the gyroscope about the axis C-C.

Precessing of the gyroscope about the axis C-C is effected by hydraulic pressure acting upon the valve 65 and through the valve stem creating a force on the gyroscope. For this purpose the valve 66 is reduced at 66e and 66d in diameter to form in eiiect a piston face equa1 in area to the sum of the areas of the two shoulders formed by the successive reductions in diameter. The combined area of these two shoulders is onehalf of the area of the lower end of the valve which forms an end wall of a chamber 68g in the lower end of the plunger. A port PRPI communicates with the annular chamber 68h formed in the plunger by the reduction in diameter of the valve, and a port PPI communicates with the chamber 68g. These ports are such that irrespective of the movement of the plunger B8, they are at all times in communication with their respective chambers. The port PRPI communicates with a supply of low pressure oil utilized as a processing reference pressure1 which may conveniently be supplied and maintained constant by the reducing valve 56 (Fig. 5) with which the port PRPI is connected through passage LPl. The port PPI communicates with the pressure or force generator through the lead 48 by way of passage PPA through the frame 2, trunnion 2e, standard 3 and the connection in valve block 36.

The force generator 45 consists of a block 10 (see Figure 6) bored axially to provide a chamber for a piston valve I I. The valve 1I has three reduced portions Ila forming the stem, 1lb at the approximate longitudinal center and 1lc.

The shoulder 'I Id formed by reducing the diameter at 1 la constitutes a pressure face upon which the precessing pressure acts at all times; similarly the shoulder lie formed by reducing the diameter at Ic forms a pressure face upon which the precessing reference pressure acts at all times. rI'he force exerted upon these pressure faces are opposed; the pressure face 'Ild is twice the area oi the pressure face IIe and the processing reference pressure is twice as great as the normal precessing pressure. Therefore, the valve is normally balanced.

Through the block, there is formed a precessing pressure port FP2 which is connected to the precessing pressure port PPI in the control block .i i through the pipe d8 and passages in the standard and frame L A passage lila connects the port FP2 with the chamber 10b formed above the shoulder lid. The valve 'II controls communication between this port FP2 and an exhaust port connected to the exhaust lead 49, and a precessing reference pressure port PRPZ, connected by the lead 41 to the reducing valve 56 through which the oil under pressure for precessing the gyroscope is supplied.

From the description of the pressure faces formed on the valve EB, the interconnection of the ports to these pressure faces, and the relation of the precessing reference pressure and the normal precessing pressure, it will be apparent that in the condition ofthe ports illustrated in the drawings, the forces acting on the valve are equal and opposite. The precessing reference pressure is constant and the precessing pressure may be raised or lowered by manipulating the valve 'Ii of the force generator. For example, if a downward force is applied to the valve 'Il the valve is moved downwardly from the position illustrated in Figure 6, the exhaust port E5 is connected to the port PPZ for a period such that the pressure in the PP ports and chamber 63g connected thereto is reduced by an amount to balance the force applied to the valve. The force on the upper end of the valve 66 then predomina-tes by this amount and there is a downward processing force on the gyroscope proportional to the force applied to the valve 1I. Likewise, if an upward force is applied to the valve 1I, the valve is moved upwardly, from the position illustrated, the port PRPZ is placed in communication with the port PPZ until the pressure in the ports PP and the chamber 68g is increased an amount to balance the force applied to the valve. The force acting on the lower end of the valve 6-6 then predominates and there is an upward precessing force applied to the gyroscope proportional to the force exerted on the valve 1I.

It is important to note that there is no move-l ment of the valve 66 under the action of these unbalanced forces, for in accordance with the phenomena of the gyroscope, the gyroscope precesses about an axis at right angles to the axis about which the precessing force tends to rotate the gyroscope, i. e. in this instance the application of a force through the valve 66 will cause the gyroscope to rotate about the axis C-C, and similarly a force exerted by the element 9 and tending to rotate the gyroscope about the axis C-C, will cause the gyroscope t0 precess about the axis D-D.

It should also be observed that the construe tion and arrangement of the force generator is such that when not actuated manually or when the valve 1I is not acted upon by some external force, it places the system in equilibrium. Por example, if the pressure in the port PP?? is less than one-half of the pressure in the port PRPZ, then the valve l! will be moved by the superior force of the pressure of the oil in the port PRPil to open the port PRP? to the port PP? until the pressure of the oil in the port PPE is sufficient to balance the force exerted by the oil in the port PRPE and close the valve. Likewise, if the pressure ci the oil in port PP2 is more than half the pressure of the oil in the port PEPE, the valve will be moved downwardly to open the port PPZ to the exhaust until the lforces on the valve l are balanced, at which time the forces on the valve 66 are balanced.

Relief device For the purpose of avoiding large instantaneous flows of oil in the precessing and processing of the valve Eli, and to relieve sudden pressures which otherwise might be created in these lilies, as for example, when the gyroscope is rotating about the axis D-D, there is provided variable volume chambers 'lilo and "12b in the control .5

block H. These chambers are formed in a bore 'l2 in the control block by a sleeve and a dii"n ferential, slidably mounted piston lll. 'The sleeve 'i3 .makes a snug t in the bore and extends into the bore from the upper end thereof to a point approximately at the longitudinal center of the bore, the upper end of the sleeve extends above the control block and a cap lb covers the end thereof. The upper end of the sleeve is however open to the atmosphere through an opening l3nt in the wall thereof. A cap l@ closes the lower end or the bore in which the sleeve is mounted. The piston 'lfl has hollow ends and it is normally centerd the bore by centering springs 'il and 'la each secured to the piston at one end; the springs extend in opposite directions and have their other ends secured in the caps l5 and l. One part 'ith at the upper end of the piston slides in the sleeve and another part of the piston 'E30 slides in the bore below the sle-eve. The parts i317 and '63o are joined by a reduced portion 'i3d of the piston 4 which forms shoulders of differential areas, the eiective area of the shoulder on the part 'i319 being one-half of the area of the shoulder on the part lilo.

A port PRP3, which is connected to port PRP! by a passage in the control block, and to port PRPZ in the force generator l5 by passage LPA and lead 41, communicates with the annular chamber '12a formed by the reduced section of the piston. Another port PPS, connected to the port PPI by a passage in the control block and to the port PPZ by passage PPl and lead 48, communicates with the chamber '12b below the lower end of the piston. When the system is in equilibrium, the piston 'i3 is centered and balanced be cause the pressure of the oil in the port PRP3 acts upon an effective surface of one-half the area on which the oil in the port PPS acts. Il the equilibrium oi'l the system is disturbed, however, as for example, by upward movement of the valve 65 from the illustrated position, the chamber 12a expands to oiset the contraction of the chamber 68h. Also, the chamber '12b contracts to oset the effect of the expansion of the chamber 68g. Conversely, if the valve is moved downwardly from the position illustrated, the chamber 12a contracts and the chamber lib expands. Whenever during operation, there is a net precessing force on the piston valve G6, the' piston 'lll has a net force applied to it and assumes a position other than central, Vdetermined by this net force `and the spring gradient. The movement of the valve is thus effected without appreciably disturbing .that portion of the system through which the Yprocessing forces are applied to the gyroscope irrespective of the position of the piston i4.

Thus there is provided by this invention a. system associated with a gyroscope functioning both as a follow-up to control a servo-:motor responsive to relative movement of thegyroscope, and as a means for applying precession forces on the gyroscope, the follow-up being effected smoothly and without appreciable reaction on the gyroscope.

It will be obvious that various changes may be made by those skilled in the art in the details of ,.@fence pressure lines, upon rapid movement K i, the embodiment disclosed 1n the drawings vand described in detail above within the principle and scope of the invention as expressed .in the ap pended claims.

We claim:

l. In a gyroscope precessing and following mechanism, a gyroscope, a pivotally mounted support therefore having a piston compartment thereon and ports in the walls thereof, a compound diierential piston slidably mounted in said compartment in control of said ports and connected to said gyroscope, a source of liquid under constant pressure acting on one end of the piston, a source of liquid under variable pressure acting on the other end of the piston, and means for varying the pressure of said last mentioned source of liquid to vary the precessing force yon the gyroscope.

2. In a gyroscope processing and following mechanism, a gyroscope, a pivotally mounted support therefore having a piston vcompartment thereon and ports in the walls thereof, a power motor, means connecting the ports to the motor, a motor operating pressure medium communieating with said ports, means connecting the motor, to the support for actuation of the support by the motor, a differential piston control .element for vcontrolling the operation of the motor slidably mounted in said piston vcompartment and connected to said gyroscope, a source of liquid under constant pressure acting on one end 40I" the piston, a source of liquid runder pressure communicating with the compartment at the opposite end of the piston, means for varying the pressure of said last mentioned source of liquid to vary the precessing force on the gyroscope, and valve means operated by the piston control element for controlling the ports and thereby controlling the operation of the motor.

3. n a gyroscope preoessing and following mechanism, a gyroscope, a support therefore mounted for pivotal movement about two axes at right angles to `each other, the support .having a piston valve compartment and ports in the walls thereof, a hydraulic motor responsive `to relative movement of the gyroscope and support about one axis, means for connecting the motor to the support for actuation of the support by the motor, a diierential piston valve in the valve compartment and connected to the ,gyroscopa the valve controlling the interconnection of the ports ofthe valve compartment, means for eiecting the operation of the motor upon relative movement of the valve and valve compartment, a source of liquid under constant pressure communicating with the compartment to act on one i3 end of' the piston valve, a source of liquid communicating with the compartment to act on the other end of the valve, and means for Varying the pressure of said last mentioned source of liquid.

4. In a gyroscopic mechanism, a gyroscope, a support therefore, a hydraulic motor, and means for controlling the operation of the motor including a hydraulically operated valve for controlling the flow of iluid to the motor, a closed system including a hydraulic medium acting on said valve, and means for varying the pressure in said closed system in accordance with the relative movements of the gyroscope with respect to its support.

5. In a gyroscope precessing and following mechanism, a gyroscope, a supporting structure therefore including a fixed support, a member pivotally mounted on said fixed support, a second member pivotally mounted on said first member at right angles to the pivotal axis of the first member, a piston compartment including valve ports in said fixed support, a second piston compartment mounted on one of said members, motors for driving said members in accordance with the relative movement of the gyroscope and the fixed support, means for operatively connecting the motors to the members, a piston in said rst named compartment adapted to cooperate with said valve parts, a piston in said second named compartment operable by the relative movement of said gyroscope for controlling the operation of said rst named piston, and means controlled by the relative movement of said first piston and said valve ports for controlling the operation of one of said motors.

6. In a gyroscope precessing and following mechanism, a gyroscope, a support therefor including two members pivotally mounted upon axes at right angles to each other, a valve cornpartment mounted on one of said members, two valves in said compartment and connected to said gyroscope for applying precessing forces to the gyroscope about axes at right angles to each other, two hydraulic motors each connected to drive one of said members, an oil supply and means for supplying said oil under pressure to said valves and motors, means intermediate said pressure means and said valves for varying the pressure on said valves to selectively operate said valves to apply precessing forces on said gyroscope to effect precession thereof, and means operable by the movement of the gyroscope relative to the members controlling the operation of the motors for driving said members.

7. A gyroscopic precessing and following mechanism comprising a pair of standards` a frame member pivotally mounted on the standards, an outer gimbal ring within the frame pivoted to the frame on an axis at right angles to that of the frame, an inner gimbal ring pivoted to the outer gimbal ring on an axis parallel to that of the outer gimbal ring, a gyroscope pivoted within the inner gimbal ring on an axis at right angles to that of the inner gimbal ring, gear means for actuating the frame about its pivotal axis, a hydraulic motor operatively connected to the gear means, and a hydraulic system for controlling the motor including a main valve block having control ports therein, leads providing communication between certain of the ports and the motor, means for providing a hydraulic medium under pressure to the valve block, a piston valve in the valve block in control of the ports, a control member operatively attached to the gyroscope,

hydraulic means responsive to the control member? for controlling the piston valve, and hydraulic means for exerting a force on the control member and thereby applying a precessing force to. the gyroscope.

8. A gyroscopic precessing and followingmechanism comprising a pair of standards, a frame member pivotally mounted on the standards, an outer gimbal ring within the frame pivoted to the frame on an axis at right angles to that of the frame, an inner gimbal ring pivoted to the outer gimbal ring on an axis parallel to that of the outer gimbal ring, a gyroscope pivoted within the inner gimbal ring on an axis at right angles ,to that of the inner gimbal ring, gear means for actuating the frame about its pivotal axis, a hydraulic motor operatively connected to the gear means, and a hydraulic system for controlling the motor including a main valve block having control ports therein, leads providing communication between certain of the ports and the motor, Ameans for providing a hydraulic medium underv pressure' to; the valve block, apiston valve in the valve block' in control of the ports, a control member opera-. tively attached to the gyroscope, a control valve block mounted on the outer gimbal ring, a control valve in the control valve block operatively connected to the control member, a hydraulic column operatively connecting the control valve and the piston valve, and hydraulic-means for exerting a force on the control member andl thereby applying a precessing force to the gyroscope.

9. A gyroscopic precessing and following mechanism comprising a pair of standards, a framev member pivotally mounted on the standards, an outer gimbal ring within the frame pivoted to the frame on an axis at right angles to that of the frame, an inner gimbal ring pivoted to the outer gimbal ring on an axis parallel to that of the Vouter gimbal ring, a gyroscope pivoted within the inner gimbal ring on an axis at right angles to that of. the inner gimbal ring, gear means for actuating; the frame about its pivotal axis, a hydraulic motor operatively connected to the gear means,l

and a hydraulic system for controlling the motor,

including a main valve block having control ports therein, leads providing communication between certain of the ports and the motor, means fory providing a hydraulic medium under pressure to,

the valve block, a piston valve in the valve block;

in control of the ports, a control valve block mounted on the outer gimbal ring having ports communicating with the main valve block, a compound control valve in the control valve block comprising an outer tubular slide valve controlling certain of the ports and operative to control the piston valve, means for providing a normally balanced hydraulic pressure on opposite ends Aof said outer slide valve, an inner slide valve operative to vary the hydraulic pressure on one endofL pound valve slidably mounted in said compartment comprising an outer tubular valve controlling certain of said ports, means for providing a normally balanced hydraulic pressure on oppsite ends ofsaid outer valve, an inner valve slidable'in the outervalve and operative to vary the hydraulic pressure on one end of the out-e1' valve, means for providing av normally balanced hydraulic pressure on opposite ends of the inner valve, means `for varying the' pressure on one end of the inner valve, and a control member operatively connecting the inner valve and the gyroscope.

v11. In a gyroscope processing and following mechanism, a gyroscope, a pivotally mounted support therefor having a piston compartment thereon and ports in the walls thereof, compound valve slidably mounted in said com-- partment comprising an outer tubular valve controlling certain of said ports, means for providinga normally balanced hydraulic pressure on opposite ends of said outer valve, an inner valve slidable in the outer valve and operative to vary the vhydraulic pressure on one end of the outer valve, means forfproviding a normally balanced hydraulic pressure 'on opposite ends oi the inner valve, means for varying the pressure on one end of the inner valve, a control member operatively connecting the inner valve and the gyroscope, and rmeans operative to relieve unbalanced presn sure on opposite ends vof the inner valve when it is moved by the gyroscope.

12. Agyroscope precessor and icllow-up, comu prising a frame mounted to tilt about an axis, a phantom ring mounted in said frame to tilt about an axis at right angles to the aforesaid axis, a gimbal `ring mounted in said phantom ring to tilt about an axis parallel to the said axis of the phantom ring, a gyroscope mounted in said gimbal ring to tilt about an axis parallel to the axis of said frame, respective hydraulic means to tilt said frame and said phantom ring about their respective axes, and means controlled by said gyroscope and said gimbal ring to energize said hydraulic meansy proportional to and upon tilt of said gyroscope about the said axes at right angles relatively to said frame and phantom ring whereby to cause said frame and phantom ring to follow the movements of said gyroscope about said axes respectively.

13. A gyroscope precessor and follow-up, comprising a frame mounted to tilt about an axis, a

phantom ring mounted in said frame to tilt about an axis at'right angles to the aforesaid axis, a gimbal ring mounted'in said phantom ring to tilt about an axis parallel to the said axis of the phantom ring, a gyroscope mounted in said gimbal ring to tilt about an axis parallel to the axis of said frame, respective means to tilt said frame about its axis and to tilt said phantom ring about its axis in said frame, and respective means controlled by movementof said gyrosccpe about its axis in said gimbal and movement of said gimbal about its axis in said phantom ring to actuate said respective tilting v'means proportionately to and upon said movements of said gyroscope and said vgimbal ring relatively to said frame and phantom `ring whereby to move said frame and phantom ring in correspondence with the movements of the gyroscope and the girnbal ring respectively. l

le. In .a gyroscope precessing and follow-up mechanism, a pivotally mounted support, a gyroscope pivotally mounted on the support, a cylindrical valve compartment mounted on the' support, a hydraulic motor for position ig the support, a compound valve in the corr a1 ment comprising an outer valve movable to control the operation of the motor and an inner valve movable in the outer valve to control the movement oi `the .outer valve, means for genM g a pair of normally balanced pressures for applying a pair of normally balanced forces tothe inner valve, means for varrying' one oi the pressures to .unbalance the forces applied to the irner valve, and a control memberoperatively cc ecting the inner valve and the gyroscope.

.15. In a .gyroscope precessing and follow-up mechanism, a support pivotally mounted on mu! tually perpendicular axes, a gyroscope pivot-ally mounted on the support on corresponding mutui' ally perpendicular axes, two valve compartments mounted on the support, two hydraulic motore' operably connected for positioning the support about each of its respective mounting a compound valve in each compartment comprising' an outer valve movable to control the operation of a respective motor and an inner valve movable in the outer valve to control the movement of the respective outer valve, means for generating two pair oi normally balanced pressures for re-' spectively applying a pair of normally balanced forces to each inner valve, means for varying one of the pressures of each pair of pressures to unbalance the forces applied to the respective inner valves, and two control members connecting the respective inner valves to the gyroscope whereby the inner valves are moved by movement of the gyroscope relative to the support about therei spective axes and the unbalanced forces applied to the inner valves are applied as processing forces acting about the respective axes of the gyroscope.

EDWARD J. POXTRAS. JAMES D. TEAR.

REFERENSES @ETT-LED The following references are oi record in the ,le of this patent:

UNETED STATES Pl'ltll' 

